A 12 –yr-old female Goeldi's monkey (Callimico goeldii) in British Columbia, Canada was diagnosed with alveolar echinococcosis (AE) on postmortem examination. Echinococcus multilocularis has been identified in several species of nonhuman primates, most frequently Old World primates, in zoos and research facilities in Europe and Asia. The strain affecting this monkey was identified as a European haplotype, indistinguishable from E. multilocularis recently identified in several canids in British Columbia. The animal is suspected to have been exposed while living in a zoological institution in Alberta, where E. multilocularis has also been reported in urban coyotes. Alveolar echinococcosis is a zoonotic disease of increasing concern in the United States and Canada, and this disease should be considered on the differential list of any nonhuman primate exhibiting signs of abdominal pain or distension, along with diagnostic imaging consistent with cystic structures of the liver or other organs.